1. Field of the Invention
The present invention pertains to a protein beverage, and to methods of making the beverage.
2. Brief Description of the Background Art
This section describes background subject matter related to the disclosed embodiments of the present invention. There is no intention, either express or implied, that the background art discussed in this section legally constitutes prior art. Moreover, this brief description is not intended to fully describe the subject matter of this art, the reader is invited to more thoroughly examine the background to better understand what is disclosed.
Carbonated dairy products have been highly sought after, and several different kinds of products have been developed. One of the more serious obstacles to be overcome is production of a highly carbonated drink where, for example, the dissolved carbon dioxide gas at room temperature is at least half of the volume of the liquid product it is dissolved in without incurring separation out or precipitation of the dairy protein from the liquid during manufacture and handling, shipping and storage. In addition to manufacturability and shelf life, the taste of previous carbonated dairy products may generally have been adversely affected by the kind of proteins present in combination with the carbonation.
Milk contains two major protein fractions, casein, which may provide about 80% by weight of the total protein, and whey protein, which may provide about 20% by weight of the total protein. The whey protein fraction is the protein fraction which may remain soluble when the casein fraction is coagulated (such, for example, as by either enzyme or acid) and separated as cheese curd. Whey protein may include several protein fractions, including, for example, β-lactoglobulin, (α-lactoglobulin, Lactalbumin, immunoglobulins (such as IgG1, IgG2, IgA, and IgM, for example), lactoferrin, glycomacropeptides, and lactoperoxidase.
Compared to casein and soy, whey proteins may be highly soluble. Whey proteins may be the least soluble at typically about pH 4.5 to about pH 5.5, which is the isoelectic point (the pH at which the net electrical charge is zero) for whey protein. In high acid systems with a pH less than about 3.5, such as in many fruit-flavored beverages, the acid solubility of whey proteins may be especially important; however, protein precipitation may occur during the mixing period when the pH of the whey protein, which typically has a pH of about 6 to about 7, transitions through the zone of isoelectric points. Protein solubility may be affected by heat, and therefore the elevated temperatures experienced during pasteurization may also negatively affect solubility and fluidity resulting in protein precipitation or gelation.
Whey protein may have a higher biological value and/or protein digestibility corrected amino acid score (PDCAAS) than casein. The physical properties of whey proteins in the digestive tract may be quite distinct from the properties of casein. Caseins may form curds within the stomach, which curds may be slow to exit from the stomach and which curds may increase their hydrolysis prior to entering the small intestine. Alternatively, whey proteins may reach the jejunum almost immediately; however their hydrolysis within the intestine may be slower than that of caseins, so their digestion and absorption may occur over a greater length of the intestine.
The protein efficiency ratio (PER) of a protein source measures the weight gain of young animals per gram of protein eaten over a given time period. Any protein having a PER of 2.5 is considered good quality. Whey protein is considered to be a nutritionally excellent protein, as it has a PER of 3.2. Casein has a PER of 2.5, while many commonly used proteins have a PER of less than 2.5, such as soy protein (PER 2.2), corn protein (PER 2.2), peanut protein (PER 1.8), and wheat gluten (PER 0.8). The higher PER of whey protein may be due in part to the high level of sulfur-containing amino acids in whey protein. Such higher level may contribute to whey protein's ability to enhance immune-function and antioxidant status.
Whey protein is a rich source of branched chain amino acids (BCAAs), containing the highest known levels of any natural food source. BCAAs are important for athletes, since, unlike the other essential amino acids, they are metabolized directly into muscle tissue and are the first amino acids used during periods of exercise and resistance training. Leucine may be important for athletes as it may play a key role in muscle protein synthesis and lean muscle support and growth. Research suggests that individuals who exercise benefit from diets high in leucine and may have more lean muscle tissue and less body fat than individuals whose diet contains lower levels of leucine. Whey protein isolate may have approximately 45% by weight more leucine than soy protein isolate.
Whey protein is available in several forms, with preparations which may range from about 1% to about 99% whey protein. Whey protein preparations may be in an aqueous form created by the removal of casein, but often takes several other forms, such as, for example, but not by way of limitation, a whey protein extract, whey protein concentrate, whey protein isolate, or whey protein hydrolysate.
Whey protein concentrate may be prepared by removing sufficient non-protein constituents from whey by membrane filtration, so that the finished dry product may be selected to contain whey protein at a given concentration which may range from about 25% by weight to about 89.9% by weight protein.
Whey protein isolate may be obtained by removing sufficient non-protein constituents from whey by membrane filtration or ion exchange absorption, so that the finished dry product may contain about 90% by weight or more whey protein, and little, if any, fat, cholesterol, or carbohydrates (e.g., lactose). Prior to concentration and spray drying, aqueous whey protein isolate may have a whey protein concentration of about 1% by weight to about 35% by weight, and may also be essentially free of fat, cholesterol, and carbohydrates.
Whey protein hydrolysate is a whey protein preparation which may have been subjected to enzymatic digestion with a protease enzyme or limited acid hydrolysis, or a suitable mechanical breakage of peptide bonds to form smaller peptides and polypeptides, to form smaller peptides and polypeptides. The protein concentration of the whey protein hydrolysate may be dependent upon the starting material. For example, a whey protein hydrolysate prepared from an 80% by weight whey protein concentrate may have an 80% by weight protein concentration, and a whey protein hydrolysate prepared from a 90% by weight whey protein isolate may have a 90% by weight protein concentration, Not all hydrolyzed whey proteins may behave alike in a food formulation, and thus one hydrolyzed whey protein may not be interchangeable with another. The functional and biological properties of whey protein hydrolysates may vary depending upon factors, such as degree of hydrolysis and which protease enzyme is used for hydrolysis.
Although hydrolysis of whey protein may lead to increased solubility, it may also negatively impact the taste. Whey protein typically has a fresh, neutral taste which may allow it to be included in other foods without adversely affecting the taste. However, hydrolysis of whey protein may result in a very bitter taste, which may impose a practical limit on the amount of whey protein hydrolysate that can be used in a food product. Therefore, a high protein beverage made with whey protein hydrolysate may require a large amount of sweeteners, or bitter masking agents to overcome the bitter taste. However, such a large amount of sweetener may not be desirable to many consumers or the bitter aftertaste of the high protein beverage may be difficult or impossible to mask to a satisfactory extent for some applications.
Whey protein contains all of the essential amino acids, and therefore, is a high quality, complete source of protein, where complete means that whey protein contains all the essential amino acids for growth of body tissues. Since whey protein is available in forms containing little fat and carbohydrates, it may be a particularly valuable source of nutrition for athletes and for individuals with special medical needs (e.g., lactose intolerant individuals), and may be a valuable component of a diet program. Further, since whey protein may contain biologically active proteins such as the immunoglobulins, lactoperoxidase, and lactoferrin, whey protein may provide advantages over other protein sources such as soy protein.
In an effort to increase the availability and use of whey protein, efforts have been made to include whey protein drinks among currently available dairy protein drinks. In particular, efforts have been made to include whey protein as a protein source in carbonated beverages. Unfortunately, the carbonation process may generally result in destabilization of whey protein, resulting in foaming and/or gelling problems under certain conditions. As a result, the amount of whey protein that has been included in carbonated beverages has been severely limited.
An article by V. H. Holsinger in Adv. Exp. Med. Biol. 1978; 105:735-47, titled: “Fortification of soft drinks with protein from cottage cheese whey”, describes preparation of cottage cheese whey protein concentrates which have the solubility, stability, and flavor to make them suitable for fortification of soft drinks and related products. Carbonated beverages prepared with conventional beverage ingredients and containing up to 1% by weight of the total beverage of added whey protein are said to have maintained clarity, color, and flavor during 203 days of storage at room temperature. Clarity of 1% protein solutions at a pH of 2-3.4 is said to be unimpaired by heating for 6 hours at 80 degrees (without specifying ° C. or ° F.), but some structural change was said to have occurred, since an average of 37% of the protein is said to have precipitated on shifting the pH to 4.7.
Clouding or creaming agents useful for still or carbonated beverages, especially acid types are described in U.S. Pat. No. 4,790,998, issued to Marsha Schwartz on Dec. 13, 1988, and entitled: “Beverage Cloud Based On A Whey Protein-Stabilized Lipid”. The composition of matter described comprises a whey protein-stabilized lipid emulsified in an acidic aqueous solution. The important features of the patented whey protein-stabilized lipid are said to include the balancing of the lipid system, the use of whey protein at pH levels of less than 4.5, and heating and homogenizing the solution to achieve acid emulsification stability. All ingredients are said to be natural, i.e., unmodified from the form typically found in nature.
A Russian abstract by Kudryavtseva et al., in Molochnaya Promyshlennost 1981; 5: 45-46, with an English translated title of: “Carbonated whey beverage”, vaguely describes a method for the manufacture of a carbonated beverage involving the following major steps: filtration of tvorog whey containing less than 1.5% protein and 0.2% fat and with a titratable acidity of less than 75 degrees Thorner, holding for up to a day at 6-8° C., heating at 90-95° C. and holding for 15 minutes, cooling to 60° C., centrifuging, addition of unnamed ingredients, cooling to 4-6° C. and injection of CO2. The Abstract then suggests the product can be bottled in narrow-neck bottles and closed with crown cork closures. Subsequent storage is at less than 8° C.
Tvorog is a Russian soft farmer's cheese. Tvorog is commonly made by allowing raw milk to sour naturally. However, it may also be made by curdling raw milk by the addition of a starter bacterial culture or an acid. Once curdled, the tvorog may be filtered to separate the tvorog curds from the tvorog whey, which typically contains whey protein, fat and lactose.
U.S. Pat. No. 4,804,552 to Ahmed et al., issued Feb. 14, 1989, and entitled: “Carbonated Liquid Dairy Product and Method of Production Thereof” describes a method of carbonating a liquid dairy product to a level of “at least” 1.5 volumes of carbon dioxide dissolved in 10 volume of liquid dairy product, while not destabilizing the liquid dairy product. The liquid dairy product is heated to a temperature of at least 160° F. for a time not in excess of 30 minutes, followed by cooling to a temperature of less than about 50° F. The cooled liquid is then subjected to pressurized carbon dioxide to carbonate the dairy product to provide taste and mouth feel. The product is then packaged in closed containers capable of substantially retaining the degree of carbonation. The carbonated dairy product is said to be buffered to a pH of at least 4.0 while being highly carbonated but not destabilized.
U.S. Pat. No. 6,403,129, to Clark et al., issued Jun. 11, 2002, and entitled: “Carbonated Fortified Milk-Based Beverage And Method Of Making Carbonated Fortified Milk-Based Beverage For The Supplementation Of Essential Nutrients In The Human Diet”, discloses dairy or non-dairy based fortified carbonated beverage solutions that supply nutrients in the human diet. The beverage described is said to have carbonation to enhance taste, improve body and mouth-feel and aid in the stabilization of milk protein such as Lactalbumnin and Casein.
U.S. Pat. No. 7,041,327 B2, to Hotchkiss et al., issued May 9, 2006, and entitled “Carbon Dioxide as an Aid in Pasteurization”, describes processes to inhibit or reduce the growth of bacteria and other pathogens in a liquid by adding carbon dioxide to the liquid, and thermally inactivating the bacteria and other pathogens. The process is said to be applicable to a wide variety of fluids, liquids, semi-solids and solids. Prior to or simultaneously with thermal inactivation carbon dioxide (CO2) is added to the product by sparging or bubbling, preferably to obtain levels of about 400-2000 ppm. At this level of CO2, the amount of microbial death that occurs during heating in a normal pasteurization (HTST) process is said to be increased by 10% to 90% over thermal inactivation carried out without the addition of CO2 prior to the thermal inactivation step. After completion of the thermal inactivation process, the free CO2 is said to be removed.
U.S. Pat. No. 6,761,920 to Jeffrey Kaplan, issued Jul. 13, 2004, and entitled: “Process For Making Shelf-Stable Carbonated Milk Beverage”, describes an aerated or carbonated milk product drink made using a method which includes pre-heating, pressurized ultra-heat treating, subsequent carbonation with a gas or gases under pressure, and packaging into a container. The method of producing the shelf-stable carbonated milk product comprises injecting under pressure carbon dioxide gas or a mixture of gases into the milk product at low temperature of less than 10 degrees centigrade and high pressure of from 50 kPa to 200 kPa. In a typical process, the milk product is pre-heat treated at a temperature of 80° C. to 138° C., followed by ultra-heat treatment from about 138° C. to about 150° C. in a holding tank, where it is held at a pressure of 700 kPa or an appropriate pressure. The carbonation may be achieved by direct injection of sterilized, purified carbon dioxide gas in a holding receptacle, or may be injected in line. Preferably the carbonation process is carried out at 2° C.±14° C. Then the carbonated liquid is transferred to a holding tank, where it is maintained at a pressure of 450 kPa and a temperature of 2° C. to 6° C.
In the U.S. Pat. No. 6,761,920, it is said that if, for some reason, the amount of carbonation of the preheated ultra heat treated milk product is insufficient, the product may be diverted to be reprocessed through the carbonater in a return loop to a holding tank to be re-pasteurized to be within the specification. After carbonation, the product is conveyed to a packaging station for packaging into sterile containers. The pH of the product is said to be preferentially maintained at 4.0 to 5.7 during packaging operations, depending on the product. After packaging the milk product into individual containers, it is said that the milk may be further sterilized by non-toxic radiation or pasteurization; however, no enabling description of how this would be done is provided.
U.S. Pat. Nos. 6,835,402 B1 and 6,866,877 B2 to Clark et al., issued Dec. 28, 2004 and Mar. 15, 2005, entitled, respectively: “Carbonated Fortified Milk-Based Beverage and Method for Suppressing Bacterial Formation in the Beverage” and “Carbonated Fortified Milk-Based Beverage And Method For Suppressing Bacterial Growth In The Beverage”, describes dairy or non-dairy based fortified carbonated beverage solutions that are said to supply essential nutrients in the human diet. In addition to describing the composition of a beverage, the patent discloses a method of using carbonization to reduce bacterial counts and reduce degradation of essential nutrients in milk-based beverages with or without pasteurization. In one embodiment, CO2 is added pre-pasteurization to eliminate or effectively reduce the growth of bacterial colonies in the beverage and reduce degradation of nutrients if UHT pasteurization is used. If CO2 is added pre-pasteurization, it is said that CO2 must be reintroduced, since pasteurization disseminates most CO2 present. This is done by in-line addition of CO2 after the beverage's temperature is brought down from about 185° F.-215° F. to about 40° F. It is said that the CO2 concentration in the final product is preferably from about 500 ppm to about 3,000 ppm. 1,000 ppm is said to be about 0.5 volumes of carbonation per volume of liquid beverage solution, so that the final product contains about 0.25 volumes to about 1.5 volumes of carbon dioxide per volume of liquid beverage solution.
One type of carbonated dairy product for which there is increasing demand is a carbonated dairy product that provides both high juice and high protein content. The problem of protein precipitation and separation out during manufacturing, shipping, and storage, discussed above for a highly carbonated high protein drink, may be compounded when the beverage contains an additional component, such as juice. Methods are known in the art for attempting to overcome the precipitation of protein from juice beverages. However, most of these methods involve the use of stabilizers.
Fiber or other carbohydrates may be added as a protein stabilizing agent, such as pectin, cellulose gum, xanthan gum, gum arabic, carageenan, guar gum, dextrin, dextrose monohydrate, and polydextrose. While stabilizers can help prevent protein precipitation, they may have the disadvantage of increasing the viscosity of the drink due to cross-linking with naturally present calcium cations. This increased viscosity may be undesirable as it may lead to a beverage having poor organoleptic properties for at least some applications. The range of amount of stabilizer which may be used may be quite narrow. For example, at a pectin concentration of below 0.06% by weight, sedimentation may be a significant problem, whereas above it, the viscosity of the beverage may be undesirably high. The ideal amount of stabilizer must be experimentally determined for each beverage formula, and may need to be adjusted from one batch to the next. Thus, a beverage formula which does not include a protein stabilizer but generates a beverage with good protein solubility is desirable for many applications.
U.K. Patent GB 2,335,134 to Burke, published Jun. 19, 2002, entitled: “A beverage”, discloses a carbonated beverage comprising: from 5 to 20 weight % of fruit juice; carbohydrate in an amount of from 2 to 6 grams per 100 milliliter; and a soluble whey protein hydrolysate in an amount of from 5 to 20 grams per liter; the beverage containing carbon dioxide in an amount of from 4 to 6 grams per liter and having a pH of less than 3.5. The pH is adjusted with citric acid and malic acid. Protein precipitation is allegedly avoided by adjusting the amount and nature of the carbohydrate used. The carbohydrate source is stated to be most preferably dextrose monohydrate.
U.S. Pat. No. 7,101,585 B2, to Shen et al., issued Sep. 5, 2006, entitled: “Ultra High Pressure Homogenization Process for Making a Stable Protein Based Acid Beverage” describes a process for preparing a stable suspension of an acid beverage, wherein a hydrated protein stabilizing agent (A) and a flavoring material (B) are combined as a preblend (I) and combined with either a slurry of a homogenized protein material (C) or a homogenized preblend (II) of a hydrated protein stabilizing agent (A) and a slurry of a protein material (C) to form a blend and pasteurizing and homogenizing the blend. The homogenization of the blend is carried out in two stages comprising a high pressure stage of from 8000-30,000 pounds per square inch and a low pressure stage of from 300-1,000 pounds per square inch. The acid beverage composition has a pH of from 3.0 to 4.5. This beverage contains juice, but is not carbonated. Pectin is added as a stabilizer.
Published Patent Application US 2003/0099753 A1 of Yang, published May 29, 2003, describes a fruit juice based beverage composition containing a protein selected from the group consisting of whey protein isolate and a combination of whey protein isolate and whey protein hydrolysate; a carbohydrate selected from the group consisting of sucrose, fructose, high fructose corn syrup 42 (HFCS 42), HFCS 55, combination of sucrose, fructose, HFCS 42, and HFCS 55, and combinations of maltodextrin with another carbohydrate selected from the group consisting of sucrose, fructose, HFCS 42, and HFCS 55; an edible acid selected from the group consisting of citric acid, phosphoric acid, combinations of citric acid and phosphoric acid, and combinations of malic acid with another edible acid selected from the group consisting of citric acid and phosphoric acid; a fruit juice or combinations of fruit juices; various vitamins and minerals; and optional fibers and flavors and a process for making such composition. The composition containing the above ingredients are asserted to be clear, have a pH of about 4.0 or less, and have a viscosity of less than about 40 centipoises. Protein stabilizing agents are used, including pectin.
As is illustrated above, there are a number of different factors which need to be, or at least may be, considered in development of a carbonated protein and juice drink. At least one of the references appear to teach away from each other in regards to, inter alia, 1) the concentrations of protein which can be used in a carbonated protein drink, 2) the amount of carbonation which can be used (and still enable a shelf-stable beverage), and 3) the pH at which various protein-containing carbonated beverages are shelf-stable.
There is also considerable lack of detail in the processing method steps in at least some of the foregoing references described, to the extent that one of skill in the art may not be enabled to produce a desired carbonated protein and juice drink after experimentation, in view of the description. Inactivation of microbes after carbonation of the beverage may be a problem for at least some applications, requiring subsequent “recarbonation” to ensure that the beverage has the proper taste and mouth feel.